Wife Is Being Harassed At Work; What Can I Do?

My wife got a job as a salaried office manager back in March of '08. At the time of her employment, she works in the same office as the company's sales representative. Numerous times she has found the sales rep online looking at pornographic sites, and in some instances he has had made several rude comments to her, in fact one regarding the smell of a woman's genitals. Her direct supervisor personally witnessed this comment. My wife decided to finally take action some six months ago and approached the company owner. The company owner explained he would talk to the sales rep, who issued an apology to my wife with the comment that he, "didn't know you [being my wife] was such a prude." No further disciplinary action was taken. However, my wife has explained that the owner is concerned about having to take further action against the sales rep since he has gotten them some big business accounts. Over the past few months things have begun to get very challenging for my wife at work. She has begun to be literally yelled at by the owner for failing to do things she didn't need to know she should be doing, she is expected to take on tasks she has never been trained on, correct budget issues with accounts that have automatic deductions (which she doesn't control), and as of last Tuesday she was moved to an hourly employee due to missed time as a result of two-three medical issues. To make matters worse she has been told by her boss he cannot physically remember when she put in a full forty hour work week, and she needs to be doing a better job, or "I [being my wife's boss] will have to train someone else to do her [my wife] job." My wife has called me in tears, and feels like she can do nothing right. She has currently been written up for a failing to make a calculation correctly. She in fact has approached her boss and owner about being undistracted while working with the company's budget. Still the owner comes into her office to scream at her about different issues. Her boss has made mistakes which my wife has been blamed for, she attempts to explain her boss was a responsible for the mistake, which the owner plays off as her simply "passing the buck." She has been instructed to check on material and equipment that she has been trained on, but is expected to check on the equipment as a qualified employee would. My wife is extremely concerned about losing her job, and since she is the only female in the company she doesn't wish to "rock the boat" but the hostilities she is facing at work is interfering with our personal lives and causing her medical issues to become more pronounced. What can I, as her husband, do to bring this issue to a close? We depend on her income just as much as mine, but with problems that are created by this issue it is costing us more financially.